Hitachi Energy REB500
Hitachi Energy REB500 8.3.3.1 and earlier can be crashed via libexpat flaws in IEC 61850 parsing.
CISA advisory ICSA-26-279-05 says Hitachi Energy REB500 versions 8.3.3.1 and earlier are affected by two libexpat issues in IEC 61850 functionality. CVE-2024-8176 is uncontrolled recursion that an authenticated user can trigger with a crafted IEC 61850 message, causing denial of service or possible memory corruption. CVE-2025-59375, in Expat before 2.7.2, lets authenticated users force large memory allocations from a small document. Both score CVSS 3.1 6.5; the fix is version 8.3.4.0, and SSVC lists no exploitation.
- CVE-2024-8176 and CVE-2025-59375 both score CVSS 6.5.
- Authenticated IEC 61850 input can cause denial of service.
- Update REB500 8.3.3.1 and earlier to version 8.3.4.0.
- CISA SSVC lists exploitation as not observed.
Vulnerabilities mentionedAll →
- CVE-2024-81767.51%A stack overflow vulnerability exists in the libexpat library due to the way it handles recursive entity expansion in XML documentspublished
- CVE-2025-593757.51%libexpat in Expat before 2.7.2 allows attackers to trigger large dynamic memory allocations via a small document that is submitted for parsing
Full article1,002 words · extracted from cisa.gov · click to collapse
Summary
Hitachi Energy is aware of open-source software vulnerabilities that affect REB500 product versions listed in this document. These vulnerabilities can be exploited to carry out Denial of Service (DoS) attack on the product. Please refer to the Recommended Immediate Actions for information about the mitigation/remediation.
The following versions of Hitachi Energy REB500 are affected:
- REB500 vers:REB500/<=8.3.3.1 (CVE-2024-8176, CVE-2025-59375)
| CVSS | Vendor | Equipment |
|---|---|---|
| v3 6.5 | Hitachi Energy | REB500 |
| 2 Vulnerabilities |
|---|
| Uncontrolled Recursion, Allocation of Resources Without Limits or Throttling |
Background
- Critical Infrastructure Sectors: Energy
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: Switzerland
Vulnerabilities
CVE-2024-8176
A stack overflow vulnerability exists in the libexpat library used by the IEC61850 functionality supported by REB500 product. An authenticated malicious user with local access could use a crafted IEC 61850 message to exploit the vulnerability in the libexpat library. This issue could lead to denial of service (DoS) or, in some cases, exploitable memory corruption, depending on the environment and library usage.
1 Affected Product
REB500 versions 8.3.3.1 and prior
Product Status: known_affected
Remediations
Vendor fix
Update to version 8.3.4.0
Additional Metrics
Relevant CWE: CWE-674 Uncontrolled Recursion
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
CVE-2025-59375
libexpat in Expat before 2.7.2 used by the IEC 61850 functionality supported by the REB500 product allows authenticated users to trigger large dynamic memory allocations via a small document that is submitted for parsing.
2 Affected Products
REB500 versions 8.3.3.1 and prior
Product Status: known_affected
Remediations
Vendor fix
Update to version 8.3.4.0
REB500 versions 8.3.3.1 and prior
Product Status: known_affected
Remediations
Vendor fix
Update to version 8.3.4.0
Additional Metrics
Relevant CWE: CWE-770 Allocation of Resources Without Limits or Throttling
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Acknowledgments
- Hitachi Energy Internal Team reported these vulnerabilities to CISA.
Notice
The information in this document is subject to change without notice and should not be construed as a commitment by Hitachi Energy. Hitachi Energy provides no warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, for the information contained in this document, and assumes no responsibility for any errors that may appear in this document. In no event shall Hitachi Energy or any of its suppliers be liable for direct, indirect, special, incidental or consequential damages of any nature or kind arising from the use of this document, or from the use of any hardware or software described in this document, even if Hitachi Energy or its suppliers have been advised of the possibility of such damages. This document and parts hereof must not be reproduced or copied without written permission from Hitachi Energy and the contents hereof must not be imparted to a third party nor used for any unauthorized purpose. All rights to registrations and trademarks reside with their respective owners.
Support
For additional information and support please contact your product provider or Hitachi Energy service organization. For contact information, see https://www.hitachienergy.com/contact-us/ for Hitachi Energy contact-centers.
General Mitigation Factors
Recommended security practices and firewall configurations can help protect a process control network from attacks that originate from outside the network. Such practices include that process control systems are physically protected from direct access by unauthorized personnel, have no direct connections to the Internet, and are separated from other networks by means of a firewall system that has a minimal number of ports exposed, and others that have to be evaluated case by case. Process control systems should not be used for Internet surfing, instant messaging, or receiving e-mails. Portable computers and removable storage media should be carefully scanned for viruses before they are connected to a control system. Proper password policies and processes should be followed. Additional information on Industrial Control Systems Cybersecurity Best Practices can be found in the Hitachi Energy’s “Industrial Control Systems Cybersecurity Best Practices” Cybersecurity Notification. [1]
SSVC
SSVCv2/E:N/A:N/2026-09-28T14:39:04Z/
Legal Notice and Terms of Use
This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Recommended Practices
CISA recommends users take defensive measures to minimize the exploitation risk of this vulnerability.
Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolate them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most recent version available. Also recognize VPN is only as secure as its connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
Advisory Conversion Disclaimer
This ICSA is a verbatim republication of Hitachi Energy PSIRT 8DBD000247 from a direct conversion of the vendor's Common Security Advisory Framework (CSAF) advisory. This is republished to CISA's website as a means of increasing visibility and is provided "as-is" for informational purposes only. CISA is not responsible for the editorial or technical accuracy of republished advisories and provides no warranties of any kind regarding any information contained within this advisory. Further, CISA does not endorse any commercial product or service. Please contact Hitachi Energy PSIRT directly for any questions regarding this advisory.
Revision History
- Initial Release Date: 2026-09-29
| Date | Revision | Summary |
|---|---|---|
| 2026-09-29 | 1 | Initial public release |
| 2026-10-06 | 2 | Initial CISA Republication of Hitachi Energy PSIRT 8DBD000247 advisory |